A joint DOE-NCI workshop on ion beam therapy (January 2013, Bethesda, MD) identified an ambitious set of technology developments needed to support a world-class treatment program for ion beam therapy. One important requirement is the ability to provide detectors that afford single-particle registration at high data rates with hgh degree of uniformity and minimal interference with the particle beam. This would allow performing proton or ion CT prior to treatment and 2D proton/ion radiography during treatment for integrated range verification, along with beam diagnostics that have minimal interference with the primary beam. Current silicon detectors employed in first developments of proton imaging systems have major limitations in terms of maximum available detector size. Limitations also exist for currently used beam monitoring detectors that are not suitable for very fast response times at high beam intensities required for future clinical applications of particle beam scanning. We propose to develop a novel detector, the plasma panel sensor (PPS), that has the potential to remove all the barriers of existing detectors and should therefore allow particle beam radiation therapy to realize its fullest potential to be used in future clinical particle beam therapy centers. Fundamentally the proposed detectors should be inherently uniform and of low mass with fast response time. During Phase I we were successful manufacturing ultrathin-PPS glass substrates (i.e., 0.30, 0.20 and 0.026 mm thickness) with electrode pitches of 2.54 mm and 0.35 mm, corresponding to theoretical spatial resolutions of ~ 0.73 mm and 0.10 mm, respectively, as demonstrated with Geant4 Monte Carlo simulations. Sub-millimeter image resolution thus seems eminently achievable, and when combined with potentially high particle detection efficiencies could make these detectors the technology of choice for both imaging and beam monitoring sensors in the particle therapy treatment room. In this 36-month Phase II SBIR we propose to: (1) fabricate and test on a clinical beam line a series of progressively larger and higher resolution, ultrathin-PPS devices with 2D readout; (2) develop Geant4 Monte Carlo simulation models of the detector prototypes to assist in data analysis, device design refinement, and performance optimization; and (3) demonstrate that the ultrathin-PPS devices will meet the clinical requirements as summarized in our Phase-I Final Report. Meeting the target objectives of this SBIR Phase II will enable Integrated Sensors to generate the Phase III funds to produce a universal detector system that will improve both treatment efficacy and the safety of particle beam therapy with protons and ions.